Blade drive device

ABSTRACT

A blade drive device includes: a blade; a drive source that drives the blade; and a chassis that has an opening opened and closed by the blade and that houses the blade and the drive source. The drive source includes: a rotor that is rotatably supported; a stator around which a coil for excitation is wound and which applies a rotational force to the rotor. The stator is arranged to surround a periphery of the opening and has a rectangular shape.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority toInternational Patent Application No. PCT/JP2008/062859 filed on Jul. 16,2008, which claims priority to Japanese Patent Application No.2007-233367 filed on Sep. 7, 2007, subject matter of these patentdocuments is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to blade drive devices.

2. Description of the Related Art

Generally, a blade drive device for a camera includes: a board having anopening; a blade opening and closing the opening; and a drive source,such as an actuator, driving the blade (see Japanese Unexamined PatentApplication Publication No. 2006-11293). In such a blade drive device, ahigh-power actuator is employed, so that a shutter speed can beincreased.

However, the high-power actuator has a large size. Thus, there is aproblem that the size of the blade drive device is also increased byemploying such an actuator.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a bladedrive device which is reduced in size and has an improved shatter speed.

According to an aspect of the present invention, there is provided ablade drive device including: a blade; a drive source that drives theblade; and a chassis that has an opening opened and closed by the bladeand that houses the blade and the drive source, the drive sourceincluding: a rotor that is rotatably supported; a stator around which acoil for excitation is wound and which applies a rotational force to therotor, and the stator being arranged to surround a periphery of theopening and having a rectangular shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a configuration of a blade drive deviceaccording to a first embodiment;

FIG. 2 is a cross-sectional view taken along a line A-A in FIG. 1;

FIG. 3 is a cross-sectional view taken along a line B-B in FIG. 1;

FIG. 4 is a rear view of a blade drive device according to the firstembodiment;

FIG. 5 is an enlarged view of a connecting portion of iron pieces, asillustrated in FIG. 2;

FIG. 6 is a cross-sectional view of a filling portion;

FIG. 7 is an exemplary cross-sectional view of a snap fitting structure;

FIG. 8 is a front view of a configuration of a blade drive deviceaccording to a second embodiment;

FIG. 9 is a front view of the blade drive device according to the secondembodiment with a flexible print substrate being omitted;

FIG. 10 is a cross-sectional view taken along a line C-C in FIG. 8;

FIG. 11 is a cross-sectional view taken along a line D-D illustrated inFIG. 8;

FIG. 12 is a front view of a variation of the blade drive deviceaccording to the first embodiment; and

FIG. 13 is a front view of a variation of the blade drive deviceaccording to the second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A description will be given of embodiments according to the presentinvention with reference to the drawings.

First Embodiment

FIG. 1 is a front view of a configuration of a blade drive deviceaccording to a first embodiment. FIG. 2 is a cross-sectional view takenalong a line A-A in FIG. 1. FIG. 3 is a cross-sectional view taken alonga line B-B in FIG. 1. FIG. 4 is a rear view of a blade drive deviceaccording to the first embodiment. The blade drive device according tothe first embodiment includes: an upper case 10; a lower case 20; ablade 30; a rotor 40; iron pieces 50, 60L, and 60R; coils 70L and 70R;and a flexible printed circuit board 80.

The upper and lower cases 10 and 20 serve as a chassis that houses theblade 30, the rotor 40, the iron pieces 50, 60L, and 60R, and a part ofthe flexible printed circuit board 80, as illustrated in FIGS. 2 and 3.The upper and lower cases 10 and 20 are made of a synthetic resin. Theupper case 10 is thicker than the lower case 20. The blade drive deviceaccording to the first embodiment is attachable to an image pickupapparatus or a lens drive apparatus so that the upper case 10 faces theobject side and the lower case 20 faces an image pickup element such asa CCD. The upper and lower cases 10 and 20 are respectively providedwith openings 11 and 21 for shooting. A slope portion 12 is providedaround the opening 11, as illustrated in FIG. 3. Additionally, the uppercase 10 is indicated by a broken line in FIG. 1.

The blade 30 is made of a synthetic resin. The blade 30 is supported toopen and close the openings 11 and 21. The blade 30 swings together withthe rotor 40. The blade 30 illustrated in FIG. 1 is positioned at areceded position, which is receded from the openings 11 and 21, and iscausing the openings 11 and 21 to be fully opened.

The rotor 40 is magnetized with differential magnetic poles in thecircumferential direction, and is rotatably supported within the upperand lower cases 10 and 20 serving as a chassis. The rotor 40 has acylindrical shape. A stopper member 41 is fitted into an innercircumference of the rotor 40. Thus, the rotor 40 rotates in conjunctionwith the stopper member 41.

The stopper member 41 has a substantially cylindrical shape made of asynthetic resin. The inner circumference of the stopper member 41 isslidably engaged with a rotor supporting shaft 13 extending in theoptical path direction, from the upper case 10. In this manner, therotor 40 is rotatably supported. As illustrated in FIG. 3, the stoppermember 41 is provided with a pin portion 411 extending radially outwardfrom a bottom of the stopper member 41. The pin portion 411 extendsradially outward beyond the outer circumferential surface of the rotor40. Additionally, the blade 30 is engaged with the bottom portion of thestopper member 41. The rotation of the stopper member 41 allows theblade 30 to swing about the rotor supporting shaft 13. Therefore, therotation of the rotor 40 swings the blade 30 to open and close theopenings 11 and 21. Additionally, the upper case 10 is provided withrestricting pins 14L and 14R contactable with the pin portion 411, asillustrated in FIGS. 1 and 3. By causing the pin portion 411 to becontact with the restricting pins 14L and 14R, the rotational range ofthe rotor 40 is restricted. Thus, the swinging range of the blade 30 isalso restricted. Further, the lower case 20 is provided with a releasinghole 24 for receiving the thickness of the pin portion 411, asillustrated in FIG. 4. Furthermore, the rotor supporting shaft 13 isengaged with an engagement hole provided in the lower case 20.

The iron pieces 50, 60L, and 60R are arranged along the inner sidesurfaces of the upper and lower cases 10 and 20. The iron pieces 50,60L, and 60R surround a substantially entire periphery of the openings11 and 21 except for the rotor 40. The iron pieces 50, 60L, and 60R areconnected to one another. The iron piece 50 has a substantially lateralU shape, as illustrated in FIG. 1. The iron pieces 60L and 60R arerespectively connected to end portions of the iron piece 50, asillustrated in FIGS. 1 and 2. The iron pieces 60L and 60R arerespectively provided with magnetic poles 62L and 62R facing the outercircumferential surface of the rotor 40. Specifically the iron pieces60L and 60R are connected to end portions of two opposed sides of theiron piece 50, and then orthogonally arranged to the two opposed sides.The iron pieces 60L and 60R are arranged to face each other. Inaddition, the iron piece 60L is omitted in FIG. 2.

The iron piece 50 has right-and-left arm portions around which coils 70Land 70R are respectively wound. The coils 70L and 70R are provided forexciting the iron pieces 50, 60L, and 60R. The magnetic poles 62L and62R are excited to be different poles by energization of the coils 70Land 70R, effecting a magnetically attractive force or magneticallyrepulsive force on the rotor 40. Therefore, the rotational force isgiven on the rotor 40. In other words, the iron pieces 50, 60L, and 60Rentirely serve as a stator giving the rotational force to the rotor 40.Accordingly, the rotor 40, the iron pieces 50, 60L, and 60R, and thecoils 70L and 70R serve as an actuator, which is a drive source drivingthe blade 30.

Additionally, all of the iron pieces 50, 60L, and 60R are arranged in asubstantially rectangular shape when viewed in the optical pathdirection. Accordingly, the upper and lower cases 10 and 20 each areformed in a rectangular shape when viewed in the optical path direction.The blade 30 is arranged at such a position as to be surrounded by theiron pieces 50, 60L, and 60R. Further, each of the iron pieces 50, 60L,and 60R has a flat shape in the optical axis direction. Furthermore, thecoils 70L and 70R are wound around the iron piece 50, whereas the coilis not wound around the iron pieces 60L and 60R. The iron pieces 60L and60R each has an identical shape.

As illustrated in FIGS. 1, 3, and 4, a flexible printed circuit board 80(hereinafter referred to as a FPC) is inserted into the upper and lowercases 10 and 20. The FPC 80 has flexibility. The FPC 80 is provided withsolder lands 81L, 81R, 82L, and 82R for energizing the coils 70L and 70Rat its surface facing the lower case 20. The both ends of the coil 70Lare respectively connected to the solder lands 81L and 82L. Similarly,the both ends of the coil 70R are respectively connected to the solderlands 81L and 82L. The solder lands 81L, 81R, 82L, and 82R are housedwithin the upper and lower cases 10 and 20 serving as a chassis, and aresurrounded by the iron pieces 50, 60L, and 60R. The FPC 80 is providedwith an attachment hole 87. As illustrated in FIGS. 1 and 3, asupporting pin 17 formed in the upper case 10 is inserted into theattachment hole 87. Further, the supporting pin 17 is engaged with anengagement hole 27, as illustrated in FIGS. 3 and 4. Therefore, thesupporting pin 17 functions to connect with the engagement hole 27, andalso functions to fix the FPC 80 at a given position.

Additionally, as illustrated in FIG. 3, the FPC 80 is inserted into theupper and lower cases 10 and 20 via an insert hole 18 formed in theupper case 10. The FPC 80 is fixed along the inner surface of the uppercase 10, via a carve portion 88 before reaching the iron piece 50.

Next, a description will be given of the iron pieces 50, 60L, and 60R.FIG. 5 is an enlarged view of a connecting portion of the iron pieces 50and 60R, as illustrated in FIG. 2. As illustrated in FIG. 5, at theconnecting portion of the iron pieces 60R and 50, thin portions 51R and61R are in contact with each other. The thin portions 51R and 61R arethinner than another portion of the iron pieces 50 and 60R,respectively. In addition, the thin portions 51R and 61R arerespectively formed with fitting holes 55R and 65R. A fixing pin 15R,which is formed in the upper case 10, is inserted into the fitting holes55R and 65R. Further, an end portion of the fixing pin 15R is pressurebonded with a bottom edge surface of the iron pieces 50R by thermalcaulking, whereby the thin portions 51R and 61R are in pressure contactwith each other. This configuration also applies to the fitting holes55L and 65L, and a fixing pin 15L.

Furthermore, as illustrated in FIG. 5, the upper case 10 is providedwith an engagement pin 16R adjacent to the fixing pin 15R. Theengagement pin 16R is engaged with engagement recess portions 56R and66R, which are respectively provided in the thin portions 51R and 61R.Unlike the fitting holes 55R and 65R, the engagement recess portions 56Rand 66R are cut out at peripheral surfaces of the iron pieces 50 and 60Rin the optical axis direction. This configuration also applies to anengagement pin 16L, and engagement recess portions 56L and 66L.

Furthermore, as illustrated in FIG. 4, filling portions which are filledwith adhesive materials A are provided at two corner portions on adiagonal line of the upper and lower cases 10 and 20. FIG. 6 is across-sectional view of the filling portion. As illustrated in FIGS. 4and 6, the filling portion is defined by an embankment portion 19, abending portion 29, and an inner peripheral surface of the cornerportion of the upper case 10. The embankment portion 19, having aprojective shape, is raised toward the lower case 20 from the upper case10. The bending portion 29 is carved toward the upper case 10 at anouter edge portion of the lower case 20. The upper and lower cases 10and 20 are fixed by the adhesive material a filled in the fillingportions.

Next, a brief description will be given of an assembling method of theblade drive device according to the first embodiment. Firstly, the rotor40, the stopper member 41, and the blade 30 are integrated with theinner side of the upper case 10 facing upwardly and are then engagedwith the rotor supporting shaft 13. Next, the iron piece 60R is arrangedinside of the upper case 10 so as to respectively engage the fixing pin15R and the engagement pin 16R with the fitting hole 65R and theengagement recess portion 66R. In the same manner, the iron piece 60L isalso arranged. In addition, the iron piece 60R is attached such that thefixing pin 15R and the engagement pin 16R are engaged with the fittinghole 65R and the engagement recess portion 66R respectively at the sametime. The engagement pin 16R serves to prevent the iron piece 60R fromrotating about the fixing pin 15R. Therefore, the iron piece 60R ispositioned relative to the upper case 10. Herein, the iron piece 60R maybe attached such that the fixing pin 15R and the engagement pin 16R arein pressure contact with each other. In this case, the iron piece 60Rhaving a desirable clearance with respect to the rotor 40 can besecurely fixed to the upper case 10. The fitting hole 65L and theengagement recess portion 66L of the iron piece 60L, and the fixing pin15L and the engagement pin 16L are provided in the same manner as theabove arrangements.

Next, the FPC 80 is attached into the upper case 10 such that the solderland 81 or the like faces the inside of the upper case 10 and thesupporting pin 17 is fitted into the attachment hole 87. Then, the ironpiece 50 wound with the coils 70L and 70R is attached to the innerperiphery of the upper case 10 such that the fixing pins 15L and 15R arerespectively fitted into the fitting holes 55L and 55R, and theengagement pins 16L and 16R are respectively engaged with the engagementrecess portions 56L and 56R. In this case, the iron piece 50 is attachedto the upper case 10 such that the thin portion 51R of the iron piece 50and the thin portion 61R are overlapped, and the thin portions 51L and61R are overlapped. Next, the end portions of the fixing pins 15L and15R are melted by thermal caulking, so the end portions of the fixingpins 15L and 15R and the outer surface of the iron piece 50 are welded.Further, in order to further securely fix the iron piece 50 to the uppercase 10, the end portions of the engagement pins 16L and 16R may bemelted by thermal caulking so as to weld with the outer surface of ironpiece 50. Next, the lower case 20 is assembled into the upper case 10such that the supporting pin 17 is engaged with the engagement hole 27and that the rotor supporting shaft 13 is engaged with an engaging holeaccording to the rotor supporting shaft 13. Then, the adhesive materialA is filled into the filling portion to bond the upper and lower cases10 and 20. As mentioned above, the blade drive device according to thefirst embodiment is assembled.

Next, a description will be mainly given of a structure for improvinghandling ability and for maintaining the reduced thickness in theoptical axis direction, according to the first embodiment of the bladedrive device. A conventional blade drive device includes: a base platehaving an opening; a blade, and an actuator for driving the blade. Theactuator is typically arranged on an edge portion, of the base plate,receded away from the opening. Thus, a stator is also arranged on theedge portion of the base plate. In a case where the stator is arrangedin such a manner, since the base plate is exposed from the outerperiphery of the blade drive device and the base plate is typicallyformed into a thin shape, the base plate may be bended depending on thehandling thereof when the blade drive device is assembled or when theassembled blade drive device is installed into an image pickup apparatusor a lens drive apparatus.

However, in the blade drive device according to the present embodiment,as mentioned above, the iron pieces 50, 60L, and 60R serving as thestator are integrated, and are formed along the inner side surfaces ofthe upper and lower cases 10 and 20. Therefore, even when the bladedrive device is tightly held at its outer periphery, the upper and lowercases 10 and 20 are hardly bent. Accordingly, the handling ability isimproved when the blade drive device is assembled and the blade drivedevice is installed into the mobile phone or the like.

Further, since the iron pieces 50, 60L, and 60R are integrated and areshaped along the inner peripheries of the upper and lower cases 10 and20, the operation of the blade 30 is ensured even when an impact isapplied to the blade drive device from its external. Therefore, theimpact resistance is improved. In particular, when the impact is appliedto the side of the blade drive device, the impact resistance isimproved. Further, the optical axis direction thickness of the upper andlower cases 10 and 20, which serve as the chassis, corresponds to thethicknesses of the coils 70L and 70R, as illustrated in FIG. 2.Typically, the coil for exciting the stator is thicker than any otherparts in the blade drive device. Therefore, the thickness of the upperand lower cases 10 and 20 corresponds to the thicknesses of the coils70L and 70R, thereby improving the handling ability and maintaining thereduced thickness in the optical axis direction.

Additionally, as illustrated in FIG. 1, the solder lands 81R, 81L, 82R,and 82L provided in the FPC 80 are housed within the upper and lowercases 10 and 20, and are surrounded by the iron pieces 50, 60L, and 60R.With such a configuration, when the blade drive device is assembled, thecoil break due to deflecting of the blade drive device can be prevented,and the handling ability is improved. Further, the FPC 80 is insertedinto the upper and lower cases 10 and 20 via these side surfaces,thereby maintaining the reduced thickness of the blade drive device inthe optical axis direction. In addition, the conventional blade drivedevice includes a drive pin, which is attached to the rotor, whichprotrudes outwardly, and which bends downwardly in the optical axisdirection. Such a drive pin is engaged with an engagement hole formed ona blade to drive the blade. In this manner, the drive pin bendsdownwardly in the optical axis direction. This is one of factors thatincrease the thickness of the conventional blade drive device in theoptical axis direction. However, in the blade drive device according tothe first embodiment, since the blade 30 is attached to the rotor 40, asillustrated in FIG. 3, the reduced thickness can be maintained in theoptical axis direction. Furthermore, this eliminates the drive pin fortransmitting the driving force from the rotor to the blade, therebydecreasing the number of the parts.

In addition, the blade 30 is directly fixed to the stopper member 41, asillustrated in FIG. 3. In the present embodiment, the blade 30 and thestopper member 41 are separately provided. However the blade 30 and thestopper member 41 may be integrated. Therefore, the number of the partscan be further reduced. In addition, in the present embodiment, therotor supporting shaft 13, which serves as a spindle for supporting therotation of the rotor 40, is integrally formed in the upper case 10.However, the invention is not limited to this configuration. Forexample, a rotor shaft which rotates in conjunction with the rotor maybe employed. In this case, the blade 30 may be directly fixed to therotor shaft, or the blade 30 may be integrally formed with the rotorshaft.

Returning to FIG. 6, the filling portions, for filing the adhesivematerial A for fixing the upper and lower cases 10 and 20, are providedin the upper and lower cases 10 and 20. In this manner, the upper andlower cases 10 and 20 are fixed by the adhesive material A. In theconventional blade drive device, a projection, which is projected in theoptical axis direction, is formed in one of the upper and lower cases 10and 20. A fitting hole, which is fitted with the projection, is formedin the other of the upper and lower cases 10 and 20. The end portion ofthe projection, which is fitted into the fitting hole, is welded bythermal caulking, thus the both are fixed. In this manner, the fixationby thermal caulking causes the end portion of the projection to beslightly melted. This is one of factors that increase the thickness inthe optical axis direction. However, as the blade drive device accordingto the present embodiment, the upper and lower cases 10 and 20 are fixedby an adhesive material, the reduced thickness can be maintained in theoptical axis direction.

Further, although the upper and lower cases 10 and 20 are fixed by theadhesive material, the present invention may employ anotherconfiguration. For example, the upper and lower cases 10 and 20 may befixed by snap fitting. FIG. 7 is an exemplary cross-sectional view of asnap fitting structure. As illustrated in FIG. 7, the upper and lowercases 10 and 20 may be respectively provided with an engagement piece 19s and an engagement hole 29 s corresponding to each other such that theengagement piece 19 s and the engagement hole 29 s do not exceed thethickness in the optical axis direction when the upper and lower cases10 and 20 are assembled. In this case, the space where the adhesivematerial is filled is unnecessary, thereby maintaining the reducedthickness in the optical axis direction and also reducing the size inthe planar direction perpendicular to the optical axis direction.

Additionally, since the iron pieces 50, 60L, and 60R, serving as thestator, have flat shapes in the optical axis direction, as illustratedin FIGS. 2 and 3, the reduced thickness can be maintained in the opticalaxis direction. In particular, as illustrated in FIG. 5, in theconnecting portion of the iron piece 50 and the iron pieces 60L and 60R,the thin portions 51L and 51R of the iron piece 50 are respectivelyoverlapped with the thin portions 61L and 61R in the optical axisdirection, when the iron pieces 60L and 60R are connected to the ironpiece 50. Therefore, the reduced thickness can be maintained in theoptical axis direction.

As mentioned above, each of the upper and lower cases 10 and 20 has arectangular shape as seen in the optical axis direction, and the ironpieces 50, 60L, and 60R are arranged to have a rectangular shape, asseen in the optical axis direction so as to correspond to the shapes ofthe upper and lower cases 10 and 20. With such a configuration, in thecase where the rectangular shape is formed, the area where the solderlands 81R, 81L, 82R, and 82L are formed is ensured widely, as comparedwith a case where a circular shape is formed as seen in the optical axisdirection. Therefore, the space for arranging components can beeffectively used. Further, the handling is facilitated after theassembly is finished.

Next, a description will be given a structure for positioning and fixingthe drive source relative to the upper case 10. As illustrated in FIGS.1 and 2, the iron pieces 50, 60L, and 60R serving as the stator arefitted onto the fixing pins 15R and 15L and the engagement pins 16R and16L so as to be positioned and fixed. Conventionally, the outerperiphery of the stator is in pressure contact with positioning pinsprovided on a board to position and fix the stator. However, when suchpositioning pins, which are in pressure contact with the outer peripheryof the stator, are provided on the board or the like, the size cannot bereduced in the planar direction perpendicular to the optical axisdirection. In the blade drive device according to the first embodiment,the fitting hole 55R or the likes, which fitted onto the fixing pin 15Ror the like, is provided in the iron piece 50 or 60R. Therefore, thepins, which come into contact with the periphery of the stator, can beeliminated, thereby reducing the size of the upper and lower cases 10and 20 in the planar direction. Accordingly, the size of the blade drivedevice can be reduced in the planar direction.

Further, as illustrated in FIG. 2, the end portion of the fixing pin 15Ris thermally caulked. This securely fixes the iron pieces 50 and 60R onthe upper case 10. In addition, since the fixing pin 15R is fitted intothe fitting hole 55R of the iron piece 50 and the fitting hole 65R ofthe iron piece 60R, even when the stator is composed of plural ironpieces, the increase in the number of the parts can be prevented, andthe size can be reduced in the planar direction.

Next, regarding the blade drive device according to the firstembodiment, a description will be given of a structure for improving theshutter speed while the smaller size is maintained.

As mentioned above, the iron pieces 50, 60L, and 60R are connected toeach other and arranged to surround substantially the entire peripheriesof the openings 11 and 21. With such an arrangement, the total length ofthe iron pieces 50, 60L, and 60R serving as the stator can be ensured,and the number of the turns of the coils 70L and 70R can be increased.Therefore, the output power of the rotor 40 is increased and the shutterspeed becomes faster. In addition, the iron pieces 50, 60L, and 60R arearranged to surround the substantially entire peripheries of theopenings 11 and 21, thereby maintaining the small size of the entireiron pieces 50, 60L, and 60R in the planar direction perpendicular tothe optical axis direction.

In addition, the iron pieces 50, 60L, and 60R are formed into asubstantially rectangular shape as a whole, thus making its linearportion as long as possible. It is therefore possible to wind the coils70L and 70R in a great number of turns around the linear portion wherethe winding is made easy. Moreover, the coils 70L and 70R are woundrespectively around two opposed sides of the iron piece 50, therebyincreasing the number of the turns of the coil. Also, the rotor 40 islocated at a center portion of one side of the rectangle. When the rotor40 is located at such a position, it is suitable for the coils 70L and70R are suited to be respectively wound around two opposing sides of theiron piece 50.

In addition, when the stator is integrally formed as the conventionalstator and is formed into a complicated shape such that the openings 11and 21 are surrounded as the blade drive device according to the presentembodiment, the winding of the coil around the stator may becomedifficult. However, the stator, which is employed in the blade drivedevice according to the present embodiment, is composed of the ironpieces 50, 60L, and 60R which are connected, as mentioned above.Therefore, the coils 70L and 70R are wound around the iron piece 50before the iron pieces 50, 60L, and 60R are connected, and then they areconnected, thereby improving the winding workability.

Second Embodiment

Next, a description will be given of a blade drive device according to asecond embodiment with reference to the drawings. Additionally, in theblade drive device according to the second embodiment, components thatare similar to those of the first embodiment will be denoted by the samereference numerals as used in connection with the first embodiment, anda detailed description of such components will be omitted.

FIG. 8 is a front view of a configuration of the blade drive deviceaccording to the second embodiment. FIG. 9 is a front view of the bladedrive device according to the second embodiment with a flexible printsubstrate being omitted. FIG. 10 is a cross-sectional view taken along aline C-C in FIG. 8.

As illustrated in FIGS. 8 and 9, a rotor 40 a is located at a cornerportion of upper and lower cases 10 a and 20 a each has a rectangularshape as seen in the optical axis direction. Additionally, iron pieces50La and 50Ra serve as a stator and each has an identical L shape. Theiron pieces 50La and 50Ra are arranged to be a rectangular shape, tosurround the periphery of openings 11 a and 21 a, and to be along innerside surfaces of the upper and lower cases 10 a and 20 a. One ends ofthe iron pieces 50La and 50Ra are respectively provided with magneticpoles 52La and 52Ra which face the rotor 40 a. Further, the other endsof the iron pieces 50La and 50Ra are connected to each other. The ironpieces 50La and 50Ra are respectively provided with fitting holes 55Laand 55Ra, which are respectively engaged with fixing pins 15La and 15Raformed in the upper case 10 a. The fixing pins 15La and 15Ra areprovided near a stopper member 41 a.

A coil bobbin 90 a is assembled onto the iron pieces 50La and 50Ra. Thecoil bobbin 90 a is made of a synthetic resin. As illustrated in FIGS. 8and 9, the coil bobbin 90 a includes: two arm portions around which thecoils 70La and 70Ra are respectively wound; flange portions 91La and92La provided at both ends of one of the two arm portions; and theflange portions 91Ra and 92Ra are provided at both ends of the other ofthe two arm portions. As illustrated in FIG. 9, the flange portions 91Laand 91Ra are respectively provided with terminal portions 94La and 94Rafor respectively winding ends of the coils 70La and 70Ra. Herein, thecoils 70La and 70Ra are composed of a single wire. This wire isconnected to solder lands 81 a and 82 a formed on a FPC 80 a, and isindicated by a dashed line in FIG. 8. Further, the coil bobbin 90 a isprovided with a thin portion 93 a connecting the flange portions 92Laand 92Ra. The thin portion 93 a is thinner than other portions such asthe flange portion 92La, and is bendable. The coil bobbin 90 a is bendedvia the thin portion 93 a such that the flange portions 92La and 92Raare perpendicular to each other, as illustrated in FIGS. 8 and 9.

Further, the FPC 80 a is provided with a relief opening 86 a forensuring an optical path passing through the openings 11 a and 21 a, asillustrated in FIG. 8. The FPC 80 a is provided with a relief opening 84a for preventing the interference with the rotation of the rotor 40 a.The FPC 80 a are provided with through holes 85La and 85Ra through whichthe fixing pins 15La and 15Ra are penetrated. FIG. 11 is across-sectional view taken along a line D-D illustrated in FIG. 8. Asillustrated in FIG. 11, the FPC 80 a is inserted into the upper andlower cases 10 a and 20 a via an insert hole 18 a formed in the uppercase 10 a. The FPC 80 a is bended at a bending portion 88 a and arrangedalong the inner surface of the lower case 20 a. Moreover, the solderlands 81 a and 82 a are arranged within the upper and lower cases 10 aand 20 a to be surrounded by the iron pieces 50La and 50Ra.

Further, as illustrated in FIG. 11, the fixing pin 15La is fitted intothe fitting hole 55La formed in the iron piece 50La, an end portion ofthe fixing pin 15La is fixed in the upper case 10 a by thermal caulking.This configuration also eliminates a positioning pin which abuts withthe periphery of the stator, thereby maintaining the small sizes of theupper and lower cases 10 a and 20 a in the planar direction.Accordingly, the small size of the blade drive device in the planardirection can be maintained. Additionally, the fixing pin 15La may bepress fitted into the fitting hole 55La. In this case, the iron piece50La can be securely fixed to the upper case 10 with a desirable certainclearance between the iron piece 50La and the rotor 40 a.

Furthermore, the blade 30 a is fixed to the stopper member 41 a, and thestopper member 41 a is rotated in conjunction with the rotor 40 a, asillustrated in FIG. 10. That is, the blade 30 a is attached to the rotor40 a via the stopper member 41 a. Also, referring to FIG. 10, thinportions 51La and 51Ra are formed on the connecting portions of the ironpieces 50La and 50Ra, respectively. Further, stage portions 16 a and 26a for supporting this connecting portion are respectively formed in theupper and lower cases 10 a and 20 a. The stage portions 16 a and 26 arespectively abut with the upper surface of the thin portion 51La andthe lower surface of the thin portion 51Ra. In addition, the coil bobbin90 a and the coil 70La are omitted in FIG. 10.

The blade 30 a illustrated in FIG. 9 is positioned at a receded positionin which the blade 30 a is receded from the openings 11 a and 21 a. Theblade 30 a in the receded position is arranged to partially overlap theiron piece 50Ra in the optical path direction. In more details, theblade 30 a is arranged between the iron piece 50Ra and the lower case 20a in the optical path direction. With such a configuration, the smallsize in the planar direction can be maintained. Furthermore, asillustrated in FIG. 9, both of the coils 70Ra and 70La are wound in sucha position not to interfere with the blade 30 a positioned at thereceded position. Accordingly, the small size in the planar directioncan be maintained.

Moreover, the coil bobbin 90 a is bendable via the thin portion 93 a, asmentioned above. Even when the stator has a rectangular shape in thismanner, the coil can be wound around two sides, which do not oppose toeach other, of the stator having the rectangular shape. Therefore, thenumber of the turns of the coil can be increased by means of the singlecoil bobbin 90 a.

Next, a description will be given of a variation of the blade drivedevice according to the first embodiment with reference to FIG. 12. FIG.12 is a front view of the variation of the blade drive device accordingto the first embodiment. FIG. 12 corresponds to FIG. 1. As illustratedin FIG. 12, a control IC 100, for controlling current in the coils 70Land 70R, is mounted on a FPC 80A. The control IC 100 is mounted on asurface, of the FPC 80A, facing the lower case 20. In this manner, thecontrol IC 100 is also mounted to be surrounded by the iron pieces 50,60L, and 60R, thereby improving the handling ability of the blade drivedevice. Also, the control IC 100 is housed within the upper and lowercases 10 and 20, thereby making the blade drive device and the controlIC 100 into a single unit, and thereby making the handling of the bladedrive device easy. Further, the space within an external device equippedwith the blade drive device can be effectively used.

Next, a description will be given of a variation of the blade drivedevice according to the second embodiment with reference to FIG. 13.FIG. 13 is a front view of a variation of the blade drive deviceaccording to the second embodiment. FIG. 13 corresponds to FIG. 8. Asillustrated in FIG. 13, a control IC 100 a, for driving the rotor 40 a,is mounted on a FPC 80Aa. The control IC 100 a is also mounted on asurface, of the FPC 80Aa, facing a lower case 20 a. With such aconfiguration, the handling ability of the blade drive device is alsoimproved. Further, the blade drive device and the IC 100 a can beintegrated into a single unit, thereby making the handling of the bladedrive device easy and effectively using space within an externalapparatus equipped with the blade drive device.

While the preferred embodiments of the present invention have beenillustrated in detail, the present invention is not limited to theabove-mentioned embodiments, and other embodiments, variations andmodifications may be made without departing from the scope of thepresent invention.

The blade defines the fully open and close states. However, the blademay adjust the opening rate of the opening. Plural blades may beprovided.

The embodiments have illustrated the blade 30 made of a synthetic resin.However, the blade 30 may be made of a typically antireflective film ofa light shielding film, like a somablack film (Somar Corporation), forexample.

Additionally, plural motors may be provided. For example, as describedin the second embodiment, when the two iron pieces each has a L shape,the two rotors are arranged on a diagonal line with the opening set as acenter.

The second embodiment has illustrated the configuration in which theiron pieces 50La and 50Ra are supported by the stage portions 16 a and26 a. However, a fixing pin formed in the upper case may be fitted intothe fitting holes formed in the iron pieces 50La and 50Ra, and then anend portion of the fixing pin may be fixed to the fitting holes bythermal caulking. Alternately, by pressure fitting the fixing pin intothe fitting hole, the iron pieces 50La and 50Ra may be securely fixed tothe upper case.

The second embodiment has illustrated the terminal portions 94La and94Ra, around which the end portions of the coils 70La and 70Ra arerespectively wound, are provided in the flange portions 91La and 91Ra ofthe coil bobbin 90 a, respectively. However, the coil bobbin without theterminal portions 94La and 94Ra may be employed.

Further, a sheet of a ND filter may cover the opening.

Finally, several aspects of the present invention are summarized asfollows.

According to an aspect of the present invention, there is provided ablade drive device including: a blade; a drive source that drives theblade; and a chassis that has an opening opened and closed by the bladeand that houses the blade and the drive source, the drive sourceincluding: a rotor that is rotatably supported; a stator around which acoil for excitation is wound and which applies a rotational force to therotor, and the stator being arranged to surround a periphery of theopening.

With such a configuration, the stator is arranged to surround theperiphery of the opening, reducing the size of the blade drive device inthe planar direction perpendicular to the optical axis direction, andensuring the entire length of the stator. This increases the number ofcoil turns. Therefore, the blade drive device can be reduced in size andthe shutter speed can be improved. Further, since the blade and thedrive source are housed in the chassis, the blade drive device can bemade to be a single unit. Thus, this facilitates an assemblingworkability of this blade drive device assembled into a variety of lensdrive devices or the like.

In the above configuration, the stator may have a rectangular shape.

The stator has a rectangular shape, thereby making one side of thestator as long as possible. Thus, the coil can be wound around a linearportion, around which the coil is readily wound, in such a manner thatthe number of coil turns is large.

In the above configuration, the coil may be wound at least two sides ofthe stator.

The coil is wound around two sides of the rectangular-shaped stator,thereby increasing the number of coil turns.

In the above configuration, the rotor is located at a center portion ofone side of the stator, and the coil is wound around two opposing sidesof the stator.

This configuration can also increase the number of coil turns.

In the above configuration, the rotor may be located at a corner portionof the stator, the coil may be wound around two sides of the stator, andthe two sides do not oppose to each other.

This configuration can also increase the number of coil turns.

In the above configuration, the stator may have a flat shape in anoptical direction.

This configuration can maintain the reduced thickness in the opticalaxis direction.

In the above configuration, the stator may include a plurality of ironpieces mutually connected, and each of the plurality of iron pieces mayhave a thin portion thinner than another portion at a connecting portionwhere the plurality of iron pieces are connected to each other.

With such a configuration, the plural iron pieces are connected at theirthin portions, thereby maintaining the reduced thickness in the opticalaxis direction.

In addition, in a case where a stator is integrally formed and has acomplicated shape to surround the periphery of the opening, theworkability of winding a coil around the stator may be difficult.However, since the stator is composed of the iron pieces connected, thecoil is wound around any of the iron pieces before the iron pieces areconnected. Then, the iron pieces are connected to improve theworkability in winding a coil.

In the above configuration, the blade may be positioned at a recededposition receded from the opening with overlapping the stator in anoptical axis direction.

This maintains the reduction in size in the planar direction.

In the above configuration, the coil may be wound around at a positionwhere the stator does not interfere with the blade positioned at thereceded position.

This maintains the reduction in size in the planar direction.

In the above configuration, a control IC for controlling energization ofthe coil may be mounted on the printed substrate, and the control IC maybe housed in the chassis and surrounded by the stator.

With such a configuration, the blade drive device and the control IC canbe unitized and its handling can be facilitated. Further, a space in anexternal device equipped with the blade drive device can be effectivelyused.

What is claimed is:
 1. A blade drive device comprising: a blade; a drivesource that drives the blade; a chassis that has an opening opened andclosed by the blade and that houses the blade and the drive source,wherein the chassis forms a slope portion around the opening; and a pairof restricting pins that are provided on the chassis, the drive sourcecomprising: a rotor that is rotatably supported; a stopper member thatis fitted into an inner circumference of the rotor; a pin portion thatis provided on the stopper member to extend radially outward beyond anouter circumferential surface of the rotor, wherein the rotational rangeof the rotor is restricted by the pin portion contacting the pair ofrestricting pins; a stator around which a coil for excitation is woundand which applies a rotational force to the rotor, the stator comprisinga plurality of iron pieces mutually connected, and each of the pluralityof iron pieces has an identical shape and has a thin portion thinnerthan another portion at a connecting portion where the plurality of ironpieces are connected to each other with the thin portions in contactwith each other, and the stator being arranged to surround a peripheryof the opening and having a rectangular shape.
 2. The blade drive deviceof claim 1, wherein the coil is wound at least two sides of the stator.3. The blade drive device of claim 1, wherein the stator has a flatshape in an optical axis direction.
 4. The blade drive device of claim1, wherein the blade is positioned at a receded position receded fromthe opening with overlapping the stator in an optical axis direction. 5.The blade drive device of claim 1, wherein a control IC for controllingenergization of a coil is mounted on a printed substrate, and thecontrol IC is housed in the chassis and is surrounded by the stator. 6.The blade drive device of claim 2, wherein the rotor is located at acenter portion of one side of the stator, and the coil is wound aroundtwo opposing sides of the stator.
 7. The blade drive device of claim 2,wherein the rotor is located at a corner portion of the stator, the coilis wound around two sides of the stator, and the two sides do not opposeto each other.
 8. The blade device of claim 7, wherein the coil is woundaround At a position where the stator does not interfere with the bladepositioned at the receded position.
 9. A blade drive device comprising:a blade; a drive source that drives the blade; a chassis that has anopening opened and closed by the blade and that houses the blade and thedrive source, wherein the chassis forms a slope portion around theopening; and a pair of restricting pins that are provided on thechassis, the drive source comprising: a rotor that is rotatablysupported; a stopper member that is fitted into an inner circumferenceof the rotor; a pin portion that is provided on the stopper member toextend radially outward beyond an outer circumferential surface of therotor, wherein the rotational range of the rotor is restricted by thepin portion contacting the pair of restricting pins; a stator aroundwhich a coil for excitation is wound and which applies a rotationalforce to the rotor, the stator comprising a plurality of iron piecesmutually connected, and each of the plurality of iron pieces has a thinportion thinner than another portion at a connecting portion where theplurality of iron pieces are connected to each other with the thinportions in contact with each other, and the stator being arranged tosurround a periphery of the opening and having a rectangular shape,wherein the iron pieces include: a first iron piece having asubstantially U shape; and second and third iron pieces, respectively,connected to an end and another end of the first iron piece and facingthe rotor; each of the first, second, and third iron pieces has a thinportion thinner than another portion; the thin portion of the first ironpiece includes a first thin portion and a second thin portion; the firstthin portion of the first iron piece is in contact with the thin portionof the second iron piece; the second thin portion of the first ironpiece is in contact with the thin portion of the third iron piece.